How to Read a Certificate of Analysis (COA): Lot Numbers, Test Items, Third-Party Labs and ISO 17025

Quick Answer

A COA (Certificate of Analysis) is the test report for one specific lot. First check that the lot number matches the goods, then review the test items, methods, results and spec limits, and whether the lab is independent and accredited to ISO/IEC 17025. Be careful with reports that have no lot number, show identical numbers on every lot, or come only from the supplier’s own lab.

The 6 Fields to Check on a COA

Field	What to check
Lot number	Matches the goods and cartons; a report without one cannot be traced
Product name and spec	Matches the product and spec you ordered
Test items and methods	Items meet your country’s requirements; methods are recognized standards
Results and limits	Every result falls within spec
Lab and accreditation	Lab name, address, ISO/IEC 17025 accreditation and its scope
Dates and sign-off	Sampling and test dates make sense; a responsible person signs

Red Flags

No lot number, or the same lot number on every report.
Identical values on every lot, or results sitting exactly at the limit.
Test dates earlier than the production date.
Only in-house testing, with no third-party report at all.
The lab’s ISO/IEC 17025 scope does not cover the methods on the report.

When in doubt, contact the issuing lab directly to confirm that it issued the report.

Typical Tests for Bubble Tea Ingredients

Ingredient	Common tests
Tapioca pearls	Microbes, preservatives, heavy metals
Tea leaves	Pesticide residues
Jams, syrups	Microbes, preservatives, colors
Non-dairy creamer	Microbes, moisture

The exact tests depend on your country’s rules and the spec agreed between buyer and seller.

Third-Party Labs and ISO/IEC 17025

ISO/IEC 17025 is the international accreditation standard for testing and calibration laboratories. In Taiwan, lab accreditation is handled by the Taiwan Accreditation Foundation (TAF). For new suppliers and high-risk ingredients, ask for third-party reports or send samples for testing yourself.

How Lot Traceability Works

A good traceability system links a finished-goods lot number to raw material sources, production dates, test records and customers. Taiwan also has traceability rules for designated food businesses; see Taiwan food business registration.

How Tang Sugar Helps

We provide test documents and ingredient specs for your target market, with shipping paperwork prepared in one set. See the full supplier document checklist or contact us.

Note: this is general purchasing guidance, not legal advice. Regulations change, so check the latest notices from the authorities in your importing country.